Method of manufacturing white sulphite cellulose from resinous woods



Patented Sept. 9, 1924.:

' UN TED STATES} PATENT oFFlcs.

HARRY ALFTHAN, OF MANT'IA, FINLAND, ASBIGNOB TO G. A. SEBLACHIUS AKTIE- BOLAGE'I, OF'MANTTA, FINLAND, A CORPORATION OF FINLAND.

METHOD OF MLANUFAGTUBING WHITE SULPEITE CELLULOSE EBOK BESINOUS WOODS.

No Drawing.

To all whom it may concern:

Be it known that I, HARRY ALrrHAN, a I citizen of the Republic of Finland, residin at Mantta, Finland, have invented new an I! useful Improved Methods of Manufacturing- White Sulphite Cellulose from Resinous Woods, of which the following is a specification.

sulphite cellulose was hitherto generally produced by'cookin pieces or chips of the s ruce wood in a so ution of calcium bisulp ite'. Many attempts has also been made to prepare sulphite pulp from fir and similar resinous woods but without success as the lye usually used in the sulphite process does not dissolve in a suflicient manner the resinous and ligneous substances of such woods.

. This invention relates to an improved 9 method of. preparing white sulphite cellulose from fir and other. resinous woods whichresults in a fully white product the quality of which is in every respect ractically the same as that of sulphite ce ulose prepared from spruce. This result is accomplished by a special preparation of the lye used in the'boilmg' operation and fm'ther by -a suitabl adjustin'gof the pressure and temperature used during the'boiling'operaso tion. w

. Accordin to my present invention I perform the boiling of the resinous woods with a l e which coptains besides calcium bisulphrte and freesulfurous acid also sodium 8 sulphite, the latter being generally present irrits acid form (sodium bisulphite) on account of the excess of free sulfurous acid in the solution, and, furthermore, I perform the. boiling operation. atia somewhat higher pressure and somewhat lower temperature than those generally used in'manufacturing sulphitelpu jrom spruce or similar white pines. re er'ably a pressure of 5 to 6 atmospheresand 'an end .tem rature of 130 to 150 C. should be used. certaincases sodium sulfate can be substituted'for the sodi sulphite in the lye. v y

,jldf preparation of the lye is preferably performed in the following manner. When the boiler has been filled with the pieces or regulated as above described.

Application filed October 1a, 1928. Serial No. ceasoi.

chip's of fir or similar resinous woods an aqueous solution of soda ash, caustic soda, or sodium sulfate is. added in such quantity that thepercentage of soda will be at most one per cent by weight counted on the cellulose contained in the wood chips. The boiler is then filled with a solution of calcium bisulphite containing in total from 3.5 to 4.5% of sulfur dioxide and from 0.8to 1.5% sulfur dioxide combined with lime. The soda 60 previously added reacts with the free sulfurous acid in the solution toform sod um sulphite or sodium bisulphite'. Experiments with the common Scandinavian fir have shown that said lye can fully extract the 05 resinous and ligneous substances from such wood if the pressure and temperature are I wish it understood that the addition of soda to the lye can be made outside the 7 boiler and that the addition thereof can be made as sodium sul hite prepared from soda inde ndently o the solution of cal-. cium bis phite. Also the quantity of soda used in the rocess can vary within wide limits depen cut on; the qualities of the resinous woods used as raw material.

What I claim is I 1. Method of manufacturing white sulphite cellulose from fir and similar resinous woods, comprisin .preparin a lye containin in solutlon calcium bis" phite, a sodium sa t and free sulfurous acid, and performing the boiling operation with said lye at a pressure of about 5'to' 6 atmdspheresand an end temperature of about to C.

2. Method of manufacturing white sul-. phite cellulose from fir and similar resinous woods, comprising preparing a lye contamm su phite and free sulfurous acid and performing the boilin' operation with said lye at a pressure of a ut 5 to 6 atmospheres andv an end temperature of about, 130 to 150 C. v e

3. Method of manufacturing white sulphite cellulose from and similar resinous woods, comprising m xing a solution of soda with a solution containm calcium bisulphite and free sulfurous.ac1d,'and perform-- I in solution calcium bisulphlte, sodium 90 ing the boiling operation of the resinous most 1% by we ht of soda counted on the woods with said lye at a pressure of about percentage of cc ulose of the wood to be 5 to 6 atmospheres and an end temperature treated, and performing the boiling operaabout 130 to 150 C. tion with said lye at a pressure of about 5 I 4. Method of manufacturing white sulto 6 atmospheres and an end temperature of 1 phite cellulose from fir and similar resinous about 130 to 150 C. woods, comprising preparing a lye eontain- In testimony whereof I have signed my ing from 3.5 to 4.5% by weight of total sulname. fur dioxide, from 0.8'to 1.5% by weight of 1Q sulfur dioxide combined with hme, and at, HARRY ALFTHAN. 

